In relational databases using SQL, relationships are used to decompose tables into smaller structures. As a result, related information may be stored in multiple tables. It is not uncommon for normalized data models and their corresponding physical relational database systems to include joins. Joins allow the creation of rows in a virtual table that includes data selected from two different tables. SQL uses a JOIN operator to pull data from the two tables to create the virtual table. Typically, the two tables are referred to individually as the left table and the right table. However, the tables may also be referred to as outer and inner tables or left and right relations. These terms are generally considered to be symmantical equivalents. In some relational database systems, such as in the Teradata Active Data Warehousing System available from NCR Corporation, the assignee of the present invention, various costing routines may be used to choose the best plan of SQL execution. The costing routines may determine the cost of reading the rows of the left table and the cost of reading the rows of the right table. Generally, the costing routines may assume that the all rows from the left and right tables will be read.